I don't see any problem at all in what you want to do, I think its a good idea. Since its a rough area native grasses would do very nicely and be low maintenance. I would put stump killer on the cut down trees and let time take care of them.

Attractive grass areas are created by massing them in, swaths of the same kind for impact and definition.

Sideoats grama is very robust and looks wonderful massed, its easy to trim back in late winter and mine get about 3 feet tall x a foot wide, very vertical and thick, they have ornamental seeds stalks all summer but are short in spring. This makes them good for having wildflowers planted among them if you'd wish to do that.

Little bluestem is not as thick but its a very attractive grass as well and there are several available at online nursery's with more new ones all the time. I read they sell quick and its hard to keep up with demand.

For big ones, you can't beat the Muhly grasses like M. linheimerii or M. rigens. These are also easy to trim and in some zones don't need yearly trimming at all.

The Switch grasses are big and robust. There are several types on the market you might check out. I've seen them massed in and the effect is very neat, vertical and tall. You could plant smaller ones such as bluestem in front of them for some texture and interest. Mine get ornamental seed stalks starting in July and look good until I cut them back in late winter. They come around quick in spring and grow fast. Mine are about 3 ft tall right now.

Another very large grass that has stunning seed heads all summer is Giant Sacaton. Its a tough, drought loving grass. You would have to start from seed and it wouldn't make an impact for a couple years but it would end up being a permanent, easy solution. Sacaton alkali is another mounding shorter type, both of these are especially good for dry climates or difficult sites.